The present invention relates to a filter for cigarettes and the like and more particularly to a two-piece permanent cigarette filter with inexpensive disposable filter cartridges.
It has long been known that nicotine and tars in tobacco smoke have an adverse effect on the health of smokers. More and more cigarettes are being sold with built-in, dry cigarette filters. However, it has been found that hygroscopic filters such as those disclosed in U.S. Pat. Nos. 2,796,869, 2,911,984; 3,048,180, and 3,137,303 are even more effective in removing tars and nicotine from tobacco smoke. This is a considerable health benefit to those who wish to continue smoking and assists those who wish to stop smoking by reducing their customary nicotine intake to levels which they may more easily do without.
It is known that the best results with hygroscopic filters are achieved when they expand upon wetting to fill the entire chamber of their holder. However, it is difficult to ensure the proper fit of such an expandable filter in a permanent holder and prior art expandable filters, such as those disclosed in U.S. Pat. Nos. 3,048,180 and 3,137,303, have been in disposable holders.
Prior art permanent holders, such as those disclosed in U.S. Pat. Nos. 2,796,869 and 2,911,984, have bound their disposable filter cartridges by relatively expensive means, such as coating with pectin or encasement in a sleeve of foil or plastic, with a slit up the side of the sleeve to allow for expansion.
The present invention avoids the expense of making the holder disposable or encasing the filter in a special sleeve by introducing a particular grade of paper as a wrapper for the filter, which, when wet, will expand with the filter. Thus, there is provided an inexpensive, disposable filter cartridge which may be slipped into a two-piece permanent holder and moistened to expand it to the full dimensions of the chamber in the holder. No special reservoir or package of fluid, as in many prior art hydroscopic filters, is necessary because the filter of the present invention may be moistened with ordinary tap water after the two sections of the holder are joined together, such as by a set of conventional, circumferential screw threads. Any excess water may be expelled by blowing into the cigarette receiving end of the holder.
It is an object of the present invention to provide a hygroscopic filter and cigarette holder which will effectively filter the entire amount of smoke passing therethrough.
It is a further object of the invention to make the hygroscopic filter disposable and inexpensive.
Yet another object of the invention is to provide an expandable paper wrapper for a filter which will facilitate the insertion of the filter in a permanent holder without leaving any annular spaces surrounding the filter in the receiving chamber of the holder.
Still another object of the present invention is to provide a smoking filter for cigarettes or the like which removes a substantial portion of the dangerous tars and nicotine from the smoke, without materially reducing the moisture content thereof.